ARABLE WEEDS. ASSOCIATION WITH CROPS 169 

 TABLE XIV. WEEDS DISCOURAGED BY " SEEDS " CROPS. 



All the weeds classified in the above table are seriously 

 handicapped in the presence of a "seeds" crop, but some are 

 much more affected by the competition than others. Bent 

 grass (Agrostis spp.}, horsetail (Equisetum arvense}, goosegrass 

 (Galium aparine], corn mint (Mentha arvensis), and large field 

 speedwell (Veronica tournefortii} are among those that are 

 less influenced. Orache (A triplex patula}, knotgrass (Poly- 

 gonum aviculare}, willow-weed (Polygonum persecaria}, and 

 especially ivy-leaved speedwell (Veronica hedercefolia} are 

 more seriously affected, as their frequency is far less than half 

 that among all crops. Couch-grass (Agropyron repens} appears 

 to come in this latter group, but it is quite conceivable that on 

 some occasions it was overlooked, as it is difficult to dis- 

 tinguish it from some of the grasses which have a legitimate 

 place in " seeds " crops. 



The majority of these weeds are rarely present in any 

 quantity, and few of them are ever dominant Orache, goose- 

 grass, red dead nettle, corn mint, willow-weed, chickweed, 

 couch-grass and ivy-leaved speedwell were never observed 

 to be dominant among this crop throughout the course of the 

 investigation, though many of them were frequently the chief 

 weeds among other crops. Bent-grass, fat hen, horsetail, 



